1. Field of the Invention
The present invention relates to an inkjet recording apparatus and method, and more particularly, to an inkjet recording apparatus and method for performing recording by using a plurality of inks of the same color type and different coloring material densities (dark and light inks).
2. Description of the Related Art
In the field of inkjet recording apparatuses, a method is known in which, in order to obtain color images of higher quality, a plurality of types of inks of the same color type and having different densities (dark and light inks) are used. For example, systems have been proposed in which a high-definition color image is reproduced by using a combination of dark and light inks, by adding the light inks, light cyan (LC) and light magenta (LM), and the like, to a composition based on four colors, black (K), cyan (C), magenta (M) and yellow (Y).
Japanese Patent Application Publication No. 11-48462 discloses technology, for suppressing the occurrence of streak when dark and light inks are used, by using the light inks having higher permeability than the dark inks, or alternatively, by setting the ejection volume of the light inks to be greater than that of the dark inks, and thus making the diameter of the dots of the light inks greater than the diameter of the dots of the dark inks.
Japanese Patent Application Publication Nos. 11-151821, 11-348322, and 2003-019819 disclose technologies for eliminating non-uniformities and resolving restrictions on ink duty, through the selective use of combinations of dark and light inks and large and small dots, in intermediate tones.
Japanese Patent Application Publication No. 2001-121806 discloses technology which reduces the effect of granularity in highlight sections, by increasing the diameter of dots of light ink compared to the diameter of dots of dark ink.
However, the most important factor in the granularity of low-density regions is the visibility of the individual (isolated) dots scattered on the white base surface. In other words, it is desirable for the diameter of the dots of light ink to be smaller, in order to reduce the visibility of the dots in the low-density regions.
Furthermore, in the recording method disclosed in Japanese Patent Application Publication No. 2001-121806, the deposited ink volume becomes large in the Dmax region where ink is deposited to create maximum density on the surface of the recording medium (e.g., paper), and therefore, the permeation of ink solvent into the recording medium can readily give rise to cockling (a phenomenon of undulation or wrinkling of the surface of the recording medium), which means that consideration must be given to drying and fixing processes after the ejection of ink droplets.